Drill bit grinding accessory



0, 1968 B. c. WILSON 3,397,492

DRILL BIT GRINDING ACCESSORY Filed March 28, 1966 2 Sheets-Sheet lmmmlim INVENTOR. ERMA 6'. MAS'O/V 4770/?MEV 1968 B. c. WILSON 3,397,492

DRILL BIT GRINDING ACCESSORY Filed March 28, 1966 2 Sheets-Sheet 2INVENTOR. BAm/V C- W/L SON izzww ATTORNEY United States Patent 3,397,492DRILL BIT GRINDING ACCESSORY Bryan C. Wilson, 23228 Edmonds Way,Edinonds, Wash. 98020 Filed Mar. 28, 1966, Ser. No. 542,427 4 Claims.(Cl. 51-219) ABSTRACT OF THE DISCLOSURE A drill bit support to presentand to position a drill bit for grinding and sharpening by rotary drivengrinding wheel and at the periphery thereof. A substantially horizontalsupporting surface and a drill bit holding and positioning carriageslidably and pivotally mounted on said horizontal supporting surface byan open pivotal connecting means, and wherein such carriage comprises anexternally threaded rod having a longitudinally extending V-shaped slotto support the drill bit during sharpening. In connection with saidV-shaped slot, there is provided a drill bit end stop slidable therein,and an internally threaded gauge connected with said rod and alsoslidably connected with said stop to position the stop longitudinally ofsaid V-shaped slot.

My invention relates to improvements in drill supporting means forpresenting the drills, as twist drills, to a rotary driven grindingwheel to grind and thereby to sharpen the drill bits.

One of the principal objects of my invention is to provide a grindingwheel attachment for use in connection with a conventional rotary drivengrinder and which attachment is simple in construction, economical, easyto apply and install, and one which produces, with reasonable care,exceedingly accurate results in bit grinding.

Prior art structures designed to regrind or to sharpen drills have hadsuch an initial cost and have required such skill in use, that it hasbecome common practice for drill users to rely on individual skill tosharpen the drills by sight calculations only, with the drill resting ona fixed support. However, many persons did not possess the needed skilland the results have become so inaccurate that, commonly, drills arethrown away rather than resharpened when it has been found that thedrills are not operating efliciently. I

It is well known in shop practice that in order to obtain maximumeificiency and life of the drill points that the cutting edges must besubstantially identical in longitudinal projection and contour andsubstantially identical as to the angle of lip clearance or relief cutaway from the cutting edges. Any lack of uniformity in these respectsresults in one cutting edge of the two or more cutting edges on thedrill to do all of the work or all of the cutting and with very rapiddeterioration in the efiiciency of the drill bit.

It is a primary object of my invention to provide a drill grindingaccessory or attachment which can be readily secured to the fixedsupports which are commonly available and present in connection withrotary grinding wheels.

It is another primary object of my invention to provide a basesupporting means comprising two plates, the lower of which isconnectible to the usual fixed support found with grinding wheels andthe upper of which is relatively angularly adjustable thereto. Thus, theangle of the ground face of a bit, relative to its longitudinal axis,supported by attachments of my invention, can be readily determined.

Another object of my invention is to provide a separable drill bitsupport which is mounted for sliding movement relative a base supportingmeans and wherein there 3,397,492 Patented Aug. 20, 1968 is a separablepivotal connecting means between the drill bit carriage and the basesupporting means.

It is a further object of my invention to provide such a separablepivotal means which is offset relative to a radial alinement of a drillbit and a grinding wheel so that upon turning about the pivotalconnection, with one swinging movement, the drill bit cutting edge iscut and the relief lip, or the receding away surface from the cuttingedge on the drill bit ground face, is provided to a desired pattern sothat after one drill bit face is ground, succeeding faces can be groundto the same contour pattern and dimension and with the need of minimumskill on the part of the operator.

These and other objects of my invention and advantages thereof will morefully appear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame parts, and, in which:

FIGURE 1 is a side elevational view, with parts broken away, of a deviceembodying my invention;

FIG. 2 is a plan view of the structure of FIG. 1, with parts brokenaway, and with the drill bit support positioned to aline a drill bittherein substantially radially of the grinding wheel or at right anglesto the axis of the grinding wheel;

FIG. 3 is a view similar to FIG. 2 with the drill bit support angularlymoved substantially over its showing in FIG. 2;

FIG. 4 is a fragmentary elevational view taken substantially on brokenline 4-4 of FIG. 1;

FIGS. 5, 6, and 7 are sectional views taken substantially, respectively,on broken lines 55, 66, and 77 of FIG. 1;

FIG. 8 is an enlarged fragmentary view, taken substantially on brokenline 8-8 of FIG. 2, and showing a fragment of a grinding wheel and a bitbeing sharpened at the commencement of the grinding of a drill bit faceand corresponding substantially to the same position of the parts asindicated in FIG. 2 of the drawings;

FIG. 9 is a view similar to FIG. 8, taken substantially on broken line99 of FIG. 3, and after the drill bit carriage has been movedsubstantially to the position shown in FIG. 3 of the drawings;

FIG. 10 is a fragmentary plan of substantially the same parts shown inFIGS. 8 and 9; and

FIG. 11 is a frontal view of the sharpened end portion of a drill bit.

Referring now to the drawings, a conventional rotary driven grindingwheel mechanism is illustrated by a base 20, motor housing 22, safetyguard 24, adjustable tool support 26, and grinding wheel 28. Thegrinding wheel 28 is driven by any suitable electric motor within themotor housing 22 and is normally driven in a clockwise direction asviewed in FIG. 1 of the drawings.

Thus, there is provided a rotary grinding wheel having an annulargrinding surface and the axis of which grinding wheel normally liessubstantially in a horizontal plane. Disposed in fixed relation, when inuse, is the tool support 26. Thus far conventional apparatus isillustrated and described and it is in connection with such conventionalapparatus that the attachment or accessory of my invention may beutilized.

While the adjustable tool support 26 is commonly provided with manyadjustments which may be utilized and then the adjustments fixed,normally such adjustments do not provide for movements within the rangedesired in my invention. Thus, to a fixed support 26, I detachablysecure a base support comprising two hingedly interconnected platemembers 30 and 32. The plate member 30 may be the lower plate member andmay be detachably connected by any suitable means, such as C-clamps 34,to any suitable portion of the adjustable tool support 26.

The means for hingedly interconnecting plate members 30 and 32 may be inthe form of laterally spaced apart flanges 36 carried by the platemember 30 and laterally spaced apart flanges 38 depending from the platemember 32. The flanges 36 may be integral with the plate 30 and bent atan angle thereto of approximately 90 and likewise the flanges 38 may beintegral with the plate member 32 and bent downwardly at substantiallyright angles thereto. The flanges 36 and 38 are interconnected by nutand bolt means wherein one of the same is in the nature of a wing nut ora bolt having a wing head thereon for easy manual manipulation. Thus, Ihave illustrated nuts 40 and bolts 42, where the bolts 42 have wingportions 44 and the bolt portions of the bolts 42 function as a pivotmeans so that any desired angular adjustment between the plates 30 and32, within the requirements of the accessory, may obtain and after suchadjustment is determined, the nuts and bolts 4042 may be locked tomaintain a desired angular position of the substantially horizontalupper surface of the plate 32. The plate 32 is positioned relative tothe grinding wheel 28 by the use of the various attachments involved inthe normal adjustable tool support 26, the C-clamps 34, and theadjustment of the base support comprising the plate members 30 and 32. Adrill bit holding and positioning Carriage 52 (hereinafter describedmore in detail) includes a plate member 46 and such plate 46 (and inturn the drill bit holding and positioning carriage) is connected by aseparable pivotal connecting means with the plate member 32. Asillustrated, the separable pivotal connecting means comprises a pin 48,which pin 48 is carried by the plate 32. A separable bearing engagingwith said pin 48 is indicated in the drawings as a V-shaped slot 50 inthe plate 46. The pin 48 may be carried either by the plate 32 or 46 andthe slot or hearing to rest against the pin may be carried by the otherof said plates 32 and 46.

When the longitudinal axis of the drill bit holding and positioningcarriage 52 is radially alined with the grinding wheel 28 (when saidaxis is at right angles to the axis of grinding wheel 28) then the axisof the pin 48 is offset laterally. Thus, in FIG. 2 of the drawings theaxis of the pin 48 is shown lower than the longitudinal axis of thedrill bit carriage member 52. Thus, when the drill bit carriage 52 isswung from the position shown in FIG. 2, to the position shown in FIG. 3of the drawings, the drill 54 in the carriage 52 will move from theposition shown in FIG. 2 or FIG. 8 of the drawings to the position shownin FIG. 3 or FIG. 9 of the drawings. Such swing is accomplished by therelative sliding movement between the contacting faces of plates 46 and32 and with movement pivoted about the axis of the separable pivotalconnecting means comprising the pin 48 and the V-shaped slot 50.

The drill bit carriage also includes an externally threaded rod 56secured to the plate 46 and such may be readily accomplished by welding.The said externally threaded rod 56 is provided with a longitudinallyextending V-shaped slot 58, the contour of which is best illustrated inthe sectional views, FIGS. 5, 6, and 7. This V-shaped slot 58 functionsas a cradle to center and slidably support a drill bit 54 placedtherein. Also, a sliding carriage 60 is mounted for sliding travel insaid V- shaped slot 58.

The carriage 60 is provided with a head portion 62 (see FIG. a recessedportion 64 (see FIG. 6), and a trailing portion 66 (see FIGS. 1 and 7).Thus, an internally threaded circular adjusting gauge 68 may pass overthe trailing edge portion 66 (before the parts are otherwise assembled)and into the recess portion 64. Then as the internally threadedadjusting gauge 68 is threaded onto the external threads of theexternally threaded rod 56, the said gauge 68 (upon rotation in onedirection) will urge the carriage 60 toward the left in the drawings asthe forward surface of the gauge 68 engages the rear face of the head 62and will urge the carriage 60 toward the right in the drawings as therearward surface of the gauge 68 engages the forward portion of trailingportion 66.

To utilize the accessory of my invention, first the adjustable toolsupport 26 is suitably adjusted and its position fixed, and then thelower plate member 30 is attached by C-clamps 34 (or other suitablemeans), to the adjustable tool support 26. Then the drill bit carriage52 is moved into place so that the V-shaped slot engages with the pin 48carried by the plate member 32. A drill bit 54 is then positioned withinthe V-shaped slot 58 and ahead of the head 62 of the sliding carriage60. The drill bit 54 is moved with its cutting surfaces toward theannular surface of the grinding wheel 28 and an adjustment is made sothat one of the cutting edges of the drill 54 is presented to thesurface of the grinding wheel 28 and at a desired angular relationthereto. To grind the relief lip 72 and cutting edge 70 (see FIGS. 8 to10) with one positioning of the drill 54, the cutting edge 74 ispositioned in a vertical plane (see FIG. 10). Then all adjustments arefixed to retain such adjustment, including tightening of the nuts andbolts 40-42. Then the sliding carriage is adjusted so that the drill bitportion to be sharpened is not in engagement with the grinding wheel 28and then the grinding wheel 28 is caused to rotate.

A cutting edge and relief lip (as 70, 72) of the drill bit 56 to befirst ground is presented to the grinding wheel 28 by tuming of thegauge 68 and with the trailing end of the drill firmly against the head62 and with the cutting edge 74 in a vertical plane as shown in FIG. 10.After the first edge is thus ground to provide the cutting edge 70, thedrill 54 is held firmly in the V-shaped slot 58 and the drill bitcarriage 52 is swung from the position shown in FIG. 2 of the drawingsto the position shown in FIG. 3 of the drawings, and at the same timethe drill cutting edge moves relative to the grinding wheel 28 from theposition shown in FIG. 8 of the drawings to that position shown in FIG.9 of the drawings. Thus, it will be apparent that the relief lip 72 isground as the drill bit carriage 52 turns about an axis determined bythe pin 48 and the bearing for said pin provided by the V-shaped slot50. As the plate 46 .angularly moves about pivot means determined by pin48 and slot 50, the end of the drill bit being sharpened moves in thepath described by the circular line 75. Thus, either the relief lip 72may be ground first or the cutting edge 70 may be ground first as bothare ground to an arcuate path designated by line 75. As the angularposition of the drill 54 locates the location of the grinding of cuttingedge 70 and relief lip 72, the angular position of drill 64 isaccurately determined by positioning of cutting edge 74 in a verticalplane as shown in FIG. 10.

The angularity of the cutting edge 70 to the longitudinal axis of thedrill bit 54 was selected and determined by the adjustments of theadjustable tool support 26 and the adjustment between the plate members30 and 32. This adjustment is maintained after the same is oncedetermined for grinding all of the cutting edges of a given drill bit. I

After one of the cutting edges of a given drill has been made, asubsequent cutting edge may be ground on the same drill bit and whichwill match the first cutting edge as the head 62 is not touched or movedbetween the grinding of one of the cutting edges 70 and the grinding ofa subsequent matching cutting edge 74. An advantage of having aseparable pivotal connection between the plate 32 of the then fixedsupport and the plate 46 of the drill bit carriage 52 is that aftergrinding the first cutting edge 70 and the relief lip 72, the drill bitcarriage 52 may be entirely removed and the drill (if a two-fluted twistdrill) turned (and with the cutting edge 70 now in a vertical positionas respects FIG. I0) and then the plate 46 rested upon the plate 32 andthe drill bit carriage 52 moved toward the grinding wheel 28 when theparts are in the relative position shown in FIG. 2 of the drawings andmoved forward until the V-shaped slot 50 rests firmly against the pin48. The relative position of the sliding carriage 60 to the grindingWheel 28 may be maintained and such will permit the second or subsequentcutting edge 74 to be ground identical to the cutting edge 70. Also, bypivoting the drill bit carriage about the pivot means, pin 48 andV-shaped slot 50, the same contour will be provided to the relief lip 76for the second cutting edge 74 as was provided in connection with therelief lip 72 for the cutting edge 70. Also, in view of the grinding tothe circular line 75, no care is needed in presenting the cutting edge74 and relief lip 76 to the periphery of the grinding wheel 28.

From the foregoing it will now be obvious that I have provided a drillgrinding attachment for use in connection with a rotary grinding wheelillustrated by the grinding wheel 28, which has an annular grindingsurface to be employed primarily in regrinding drill bits. Twist drillbits having a plurality of cutting edges are illustrated by drill 54having cutting edges 70 and 74 and relief lips 72 and 76. Suchconventional grinding wheels are provided with an adjustable supportillustrated generally by 26 and which when in use becomes a fixedsupport which is in operative position relative to the grinding wheel28. In my invention the attachment comprises a base support which isdetachably connected to the fixed support and wherein said base supportpreferably comprises the plates 30 and 32 which are detachably connectedto the fixed support and which plates 30 and 32 are hingedlyinterconnected as by nuts 40 and bolts 42 to thus provide asubstantially horizontal supporting surface by the plate 32.

Next, I provide a drill bit holding and positioning carriage 52 whichincludes therein the plate 46 which is slidably mounted on thehorizontal supporting surface 32. The connection, between the horizontalsupporting surface 32 and the plate 46 of the drill bit holding andpositioning device 52, is preferably a separable pivotal connectingmeans including a pin, as 48, and pin receiving bearing, such asV-shaped slot 50. As illustrated, the pin 48 is carried by the plate 32and the pin receiving bearing 50 is carried by the plate 46. However, itis only necessary that the pin 48 be carried by one of said members andthe pin receiving bearing 50 by the other thereof to provide for aseparable pivotal connecting means between the drill bit holding andpositioning device, as 52, and the horizontal supporting surface, asplate 32.

Next, the axis of the pivotal connecting means is relatively offset fromthe alinement illustrated in FIG. 2 of the drawings where thelongitudinal axis of the drill bit holding and positioning carriage 52and the drill bit 54 therein is alined with a plane at right angles tothe axis of the grinding wheel 28 or as it may be stated, in the planeradial to the grinding wheel 28. By having such offset, the drill bitholding and positioning device 52, as well as the drill bit 54 carriedthereby, may be swung from the position shown in FIG. 2 of the drawingsto the position shown in FIG. 3 of the drawings which in turn providesthe relative motion between the drill bit 54 and the grinding wheel 28which is illustrated by the change from FIG. 8 to FIG. 9 of thedrawings. When the parts are in the position shown in FIG. 8 of thedrawings,- the cutting edge 70 of the drill 54 is ground and as theplate 46 is swung about the axis of the pin 48, the drill bit moves fromthe position shown in FIG. 8 of the drawings to the position shown inFIG. 9 of the drawings and the relief lip 72 is cut.

Preferably, the drill bit holding and positioning carriage 52 comprisesan externally threaded rod 56. Preferably, the threads should berelatively large in number per inch and precisely fitted to the internalthreads of gauge 68, which will minimize any tendency of the gauge 68 toturn on rod 56 because of vibration which may result from contacting ofthe drill 54 with the annular surface of the grinding wheel 28.

Next, the externally threaded rod 56 is Preferably provided with aV-shaped slot 58 for carrying and centering of a drill 54 therein.

Lengthwise movement of a drill 54 in the slot 58 and predetermining of aposition therein obtains by reason of the sliding carriage 60 whichcomprises the head 62, the recess portion 64, the trailing portion 66,and the adjusting gauge 68, the latter being internally threaded,carried in the recess portion 64, and threadedly connected with theexternal threads of externally threaded rod 56. The said gauge 68 isrotatively mounted in the recess portion 64. I believe that the mode ofoperation of the parts of my invention will be either explicit orinherent and implicit in the foregoing without further detaileddescription.

Obviously, changes may be made in the forms, dimensions and arrangementsof the parts of my invention without departing from the principlethereof, the above setting forth only a preferred form of embodiment ofmy invention.

What I claim is:

1. A drill grinding attachment for a rotary grinding wheel having anannular grinding surface, the axis of which lies substantially in ahorizontal plane and a fixed support operatively positioned relative tothe grinding wheel peripheral surface, comprising a base portiondetachably connected to said fixed support and providing a substantiallyhorizontal supporting surface; a drill bit holding and positioningcarriage slidably mounted on said horizontal supporting surface, saidcarriage comprising an externally threaded rod having a longitudinallyextending V-shaped slot, a drill bit end stop, and an internallythreaded gauge, slidably connected with said drill bit end stop andthreadedly connected with said externally threaded rod; and an openpivotal connecting means between said carriage and said horizontalsupporting surface permitting sliding movement of said carriage on said'horizontal supporting surface about the axis of the pivotal connectingmeans, the said axis lying substantially in a vertical plane andlaterally offset from a plane passing through the longitudinal axis of adrill bit on said carriage and passing substantially radially of saidgrinding wheel.

2. The combination of claim 1 wherein said carriage has a gaugereceiving recess and said gauge is mounted for rotary movement asrespects said recess.

3. The combination of claim 1 wherein said open pivotal connecting meanscomprises a pin and registering open slot pivotally interconnecting saidsupporting surface and said carriage.

4. The combination of claim 4, wherein said pin is carried by saidsupporting surface, projects upwardly therefrom, and is engageable withan open slot provided in said carriage.

References Cited UNITED STATES PATENTS 388,784 8/ 1 888 Mossberg 5 1-96X 2,119,741 6/1938 Fischer 5l96 X 2,313,641 3/ 1943 Hoerst '5 12"192,371,676 3/ 1945 Coyne 51-219 2,401,471 6/ 1946 Fendring 51-219 FOREIGNPATENTS 277,754 12/ 1951 Switzerland.

HAROLD D. WHITEHEAD, Primary Examiner.

